I'll be traveling to Scandinavia this summer and am taking my 17 yr-old nephew. What will I need for him to travel besides his passport (ie. notarized letter from parents)?
You will need a notarized Letter of Consent Form. Go to Goodle and download for free.
In addition to the form mentioned in the above post, I'd also carry a state ment authorizing you to "seek, obtain and authorize" medical care in the event it is needed. Make sure you have all his medical info (current medications, any medical conditions, etc.).
Also, be aware (and make sure his parents are aware) that in many European countries the legal drinking age is 16 (no sure about the Scandinavian countries). Their position (and yours) on this issue should be discussed prior to the trip. I'd also discuss phone/texting issues. Costs abroad can be prohibitive if you haven't checked things out beforehand.